1. Field of the Invention
The present invention relates to an electronic musical instrument for generating musical tones in accordance with various tone generation modes, and, more particularly, to an electronic musical instrument, such as an electronic keyboard, an electronic guitar or an electronic wind instrument, which generates musical tones in accordance with playing operation modes, or an electronic musical instrument having a tone generation mode in which a plurality of musical tones with a plurality of timbres are simultaneously generated in response to a note ON start command and other tone generation modes can be switched to one from another.
2. Description of the Related Art
Recently, various electronic musical instruments such as electronic keyboards, electronic guitars and electronic wind instruments have been developed.
When a player arbitrarily depresses one of a plurality of keys on a keyboard of an electronic keyboard, the electronic keyboard electronically detects and processes key-depressing data and key-depressing speed of each key as note ON/OFF data and initial touch data to generate a musical tone with arbitrary pitch, volume and timbre, and electrically detects and processes the pressure after the key depression as after touch data to arbitrarily alter the volume, timbre and the like of the musical tone. Further, the electronic keyboard electrically detects and processes operation data of a pitch bend wheel provided on the keyboard body to impart the same pitch bend effect to whole musical tones being generated and electronically detects and processes operation data of a modulation wheel, portamento pedal, volume pedal, etc. as control change data to impart multifarious effects to the musical tones.
When a player performs picking of an arbitrary one of, for example, six strings stretched on the body of an electronic guitar while depressing an arbitrary position on frets provided also on the guitar body, this guitar electronically detects and processes depressing data of the fret and vibration data of each string to ensure generation of a musical tone with an arbitrary pitch, volume and timbre in association with each string. In this case, when a choking operation or manipulation of a tremolo arm is executed, the guitar electrically detects and processes a change in pitch for each string as pitch bend data to impart a pitch bend effect for each string.
When a player blows through a mouth section called mouth piece while manipulating play switches for designating the desired pitch, an electronic wind instrument electronically detects and processes data from the switches as note ON/OFF data to generate a musical tone according to the switch operation, or electrically detects and processes the strength of the player's blowing through the mouth piece as after touch data to generate a musical tone with a volume and timbre according to the blowing strength.
Digital interfaces, such as MIDI (Musical Instrument Digital Interface), which facilitate connection between electronic musical instruments, are standardized so as to ensure control of a tone generator of one electronic musical instrument based on the musical operation of another electronic musical instrument, or ensure construct a music system having a plurality of electronic musical instruments by separating a tone generating section (hereinafter called a tone generator module) of an electronic musical instrument from the music operating section such as the keyboard, string and fret portion, mouth piece, or play switches, of this electronic musical instrument and connecting the tone generator module to these music operating sections via a MIDI or the like. Further, a music may be automatically played by replacing the music operating section with a sequencer or a computer and automatically outputting music play data to the tone generator module.
Recently developed electronic musical instruments, particularly, tone generator modules include a multi-channel mode tone generator module which can perform different tone generations in accordance with the tone generation modes of an ordinary electronic keyboard and can have a plurality of MIDI channels set therein, so that it can function as if independent tone generators are coupled to the respective MIDI channels. The use of such a tone generator module permits a sequencer or the like to be coupled to the tone generator module and permits different music play data to be independently output for the respective MIDI channels, so that a plurality of musical tones can be independently generated by a single tone generator module.
According to the aforementioned various electronic musical instruments, formats for transferring main music play data such as note ON/OFF, pitch bend, after touch, control change or timbre change, are often unified by the MIDI standards or the like so that musical instruments of not totally different types (e.g., different types of keyboards) can be mutually connected.
In a case where based on the musical operation of, for example, an electronic guitar or an electronic wind instrument, the tone generator or tone generator module of another electronic musical instruments is controlled. However, exclusive tone generators or tone generator modules are respectively required for the target electronic musical instruments. For instance, with the use of an electronic keyboard, when music play data is output based on the MIDI standards, note ON/OFF data and pitch bend data or the like are generally output in a specific MIDI channel set in advance by a player, thus requiring a tone generator module which receives music play data and generates a musical tone according to the setting. In contrast, according to an electronic guitar, the note ON/OFF data or pitch bend data for the individual strings is output in association with one MIDI channel to a plurality of consecutive different MIDI channels and musical tones for the individual strings are independently generated from the tone generator without inconsistency in the different MIDI channels. The use of the electronic guitar, therefore, requires a tone generator module which can cope with such a tone generation mode. An electronic wind instrument specifically converts after touch data on the tone generator side to control the volume of a musical tone, for example, thus requiring a tone generator module which is specifically designed for such a tone generation mode.
As described above, the conventional electronic musical instruments can only perform a particular operation for each specific tone generation mode corresponding to a musical operation mode, so that even when different types of electronic musical instruments, such as an electronic keyboard, an electronic guitar and an electronic wind instrument, which have different tone generation modes corresponding to a plurality of musical operation modes are mutually connected, it is not possible to perform the optimal tone control. When one tone generator module is to be driven, therefore, it should be connected to the music system in a manner associated with the intended tone generation mode. This restriction requires a plurality of tone generator modules for different tone generation modes.
If the outputs of the individual strings of an electronic guitar are associated with the individual MIDI channels of the aforementioned tone generator module having a multi-channel mode and musical tones are to be generated in different MIDI channels for the respective strings, musical tones may be independently generated for the individual strings and a pitch bend effect or the like may be independently imparted for each MIDI channel or each string. In a case where each MIDI channel is used in a monophonic mode (corresponding to the mono mode with omni off in the MIDI standards), for example, if one string is consecutively picked, it is not possible to perform such a control as to permit tone off with some reverberation given to the current tone so that the next musical tone can smoothly follow the current one. If each MIDI channel is designed to be polyphonic to cope with two or more tones and an electronic guitar is designed to automatically output note ON/OFF data, the required polyphonic number of the tone generator becomes doubled or greater. For instance, 12 polyphonic sounds are required for six strings, thus preventing the effective use of the tone generator. In general, many tone generator modules have a limited number of polyphonic sounds, e.g., 8 sounds, in view of cost reduction, and such tone generator modules can hardly realize the above-described operation.
Recently, in order to improve the musical expressions given by electronic musical instruments, it becomes popular to develop those electronic musical instruments which have a play mode called a combination mode in which a plurality of musical tones are simultaneously generated for a single note ON command, such as mixing of two tones, four tones, etc., or different timbres can be set by a certain key code, such as the key split.
Let us now consider a case where a musical effect such as an LFO (Low Frequency Oscillator) vibrato or LFO tremolo (growl) is imparted to a musical tone to be generated, and particularly in a case where i.e., a delay characteristic is imparted to the musical tone. According to these LFO effects, the characteristic of a musical tone, such as the pitch, volume or timbre, periodically oscillates around the pitch, volume or timbre attained at the note ON time in accordance with a low frequency waveform (LFO waveform). Particularly, the delayed LFO effect permits the individual characteristics to have a small oscillation amplitude immediate after the note ON, increase to a given amplitude level upon elapse of a predetermined delay time, and periodically change at the given amplitude thereafter.
Conventionally, recently popular electronic keyboards or the like are designed in such a way that as the number of polyphonic sounds increases to four, eight, sixteen and so forth, the LFO effects can be independently imparted in association with individual musical tones. According to electronic musical instruments having the aforementioned combination mode, it is typical to independently impart the LFO effects, such as the LFO vibrato and LFO tremolo (growl) for individual tone generating operations.
As regards the delayed LFO characteristic, with electronic keyboards or the like in use, with all musical tones being currently put off, after the LFO effect having the delay characteristic is imparted to that musical tone whose generation has started first, an LFO effect synchronous with the delay characteristic accompanying LFO effect given to the first musical tone is imparted to those musical tones following the first one. The greater the time elapsed from the start of generation of the first musical tone, therefore, the less the influence of the delay, so that the oscillation amplitude caused by the LFO effect approaches a predetermined value. Such a control mode in electronic keyboards or the like would cause no inconveniences or problems and natural musical tone would be generated.
In a case where different timbres are mixed, e.g., two or more tones are mixed and are simultaneously generated at each note ON time, however, independent LFO effects would be imparted to those musical tones which have the mentioned individual timbres and are to be generated. As a result, for the LFO vibrato, dissonance may occur, and for the LFO tremolo, an irregular swell may occur between musical tones, which is likely to inconvenience the musical performance.
As regards the delay characteristic of the LFO effects, according to electronic guitars or the like, the player's operations are independently executed for the individual strings and tone controls based on the operations are nearly independently performed for the individual strings. If the LFO effect accompanied by the delay characteristic is imparted to musical tones under such a control that the delayed LFO effect would be given to consecutively generated musical tones in synchronism with the effect given to the first generated musical tone, not only the musical expressions of the electronic guitars would be impaired but also the player and listeners would feel unpleasant.
Since the aforementioned tone generator module having a multi-channel mode basically functions as an electronic keyboard, controlling the delayed LFO effect is the same manner as given for the electronic keyboard. Simple connection of an electronic guitar or the like to this tone generator via a MIDI or the like cannot provide the LFO effect having the expected delay characteristic.